A high efficiency electro-emission device (HEED) has been developed with a structure of Pt/SiO x /Si/Al on a thermally-oxidized Si substrate. The thicknesses of the SiO x and Si films were 400 nm and 5 µ m, respectively. Electron emission characteristics of the HEED are reported. It was found that the HEED has an electron-emission efficiency as high as 28% and a high brightness of 80 kcd/m2 using phosphor ZnS:Cu,Al. This high electron-emission efficiency was obtained in a range of applied voltage in which negative resistance occurred.

We have prepared several nanometer-sized silicon colloids in the range from 3.7 to 9.8 nm with a constant weight density 1 mg/ml. The blue-green emission is found to be independent of size contrast to its intensity. The absolute quantum yield as a function of size is determined. From the proposed model that combines surface as well as volume effects, the emission is proved to be from a surface trapped site. The energy transfer efficiency from volume to the site is almost 100% for the 3.7 nm particle.

No abstract

Silicon nanoparticles dispersed in 2-propanol were prepared by using an arc plasma with gas Aow method in a new designed home-made apparatus. The particles are composed of silicon crystal core covered by oxidized amorphous silicon shell. The composition of the particle surface layer can be modified by preparing the sample in different atmosphere. The particles can be also obtained with different core composition and different size which we need.

We have prepared Si nanocolloids by trapping Si ultrafine particles (UFPs) prepared by gas evaporation into an organic solvent. The average diameter of the Si UFPs is 4.8 nm. Strong blue-green photoluminescence (PL) from the Si UFPs has been observed at room temperature. The peak energy of the broad PL band is about 2.5 eV. We have investigated the dependence of the PL intensity on the aging of the sample and the average diameter of the Si particles.